The present invention relates to specific photochromic spirodihydrophenanthropyrans and to their use in plastics of all kinds, in particular for ophthalmic purposes. The compounds of the invention are photochromic pyran compounds, which are derived from 9,10-dihydrophenanthrene. According to the invention, at least one of the two carbon atoms in position 9 or 10 belongs to an additional ring system and, thus, forms a spiro linkage point.
Different classes of dyes have existed for a long time. When these dyes are irradiated with light of certain wavelengths, in particular solar rays, they change their color reversibly. The reason is due to the fact that light energy causes these dye molecules to change over into an excited state, which they leave again when the supply of energy is interrupted and return to their initial state. These photochromic dyes include a wide variety of pyran systems, which have already been described with different base systems and substituents in the state of the art.
Pyrans, especially naphthopyrans, and larger ring systems, which are derived from said naphthopyrans, are photochromic compounds, which to date have been the object of intensive investigations. Although the first patent was filed already in 1966 (U.S. Pat. No. 3,567,605), compounds, which appear to be suitable for use in spectacle lenses, were not developed until the 1990s. A suitable class of pyran compounds is, for example, the 2,2-diaryl-2H-naphtho[1,2-b]pyrans or the 3,3-diaryl-3H-naphtho[2,1-b]-pyrans, which exhibit different hues, such as yellow, orange or reddish orange, in the excited form.
Other compound classes of photochromic compounds that are of interest include the higher annellated pyrans, which absorb longer wavelengths owing to their larger ring system and produce hues of red, violet and blue. They may be systems, which are derived from either the 2H-naphtho[1,2-b]pyrans or the 3H-naphtho[2,1-b]pyrans and which are produced from the respective naphthopyran systems by annellation on the f side.
Currently the most promising photochromic compounds are diaryl chromenes, in particular naphthopyrans or heterocyclically annellated benzopyrans, which are substituted in position 6 of the benzopyran with a phenyl ring or, more generally, with an aromatic or heteroaromatic ring, which is bridged, in addition, in the position 5 of the benzopyran by means of at least one carbon atom, oxygen atom or nitrogen atom.
If the bridging is produced with just one atom, then the result is a five membered ring, annellated to the benzopyran. Examples for a carbon atom may be found in the U.S. Pat. No. 5,645,767, U.S. Pat. No. 5,723,072 and U.S. Pat. No. 5,955,520; examples for an oxygen atom may be found in the U.S. Pat. No. 6,018,059.
In the U.S. Pat. No. 5,723,072 an unsubstituted, monosubstituted or disubstituted heterocyclic ring on the g, h, i, n, o or p side of the indenonaphthopyran may, in addition, be annellated to the base system. Hence, indeno[1,2-f]naphtho[1,2-b]pyrans with a very large variation of possible substituents are disclosed.
WO 96/14596, WO 99/15518, U.S. Pat. No. 5,645,767, WO 98/32037 and U.S. Pat. No. 5,698,141 disclose photochromic indeno-annellated naphthopyran dyes, derived from 2H-naphtho[1,2-b]pyran, the compositions thereof as well as a method for their production. Moreover, the U.S. Pat. No. 5,698,141 discloses that an unsubstituted, monosubstituted or disubstituted heterocyclic ring on the g, h, i, n, o or p side of the indenonaphthopyran may, in addition, be annellated to this base system. The very extensive list of substituents also includes very specific spiro compounds and, in particular, such systems comprising a spiro heterocyclic group, in which there is a 5 to 8 membered ring, which always contains two oxygen atoms, with the inclusion of the spiro atom at the position 13 of the base system. Another embodiment of the spiro ring is disclosed in the Japanese application 344762/2000.
If this compound is produced through two atoms, the result is an annellated six membered ring with a plurality of possibilities just for C, O and N alone. Compounds with C═O and N—R (lactam bridge) are described in the U.S. Pat. No. 6,379,591. Compounds with an unsubstituted CH2—CH2 bridge as well as an annellated heterocycle in position 7, 8 of the underlying benzopyran are disclosed in the U.S. Pat. No. 6,426,023.
U.S. Pat. No. 6,506,538 describes the carbocyclic analog compounds, where the H atoms in the bridge may be substituted with OH, (C1-C6) alkoxy or where two H atoms at a C atom may be substituted with ═O.
If this compound is produced with three atoms, the result is an annellated 7 membered ring with very many variation options because of the insertion of heteroatoms. Compounds with a CH2—CH2—CH2 bridge are described in the U.S. Pat. No. 6,558,583. In this case, too, the H atoms in the bridge may be substituted with OH, (C1-C6) alkyl or (C1-C6) alkoxy, or two hydrogen atoms at a C atom may be substituted with ═O. In the event of an identical substitution pattern they absorb shorter wavelengths than the annellated 6 membered rings.
US 2004/0094753 describes both compounds with a bridge comprising 2 as well as 3 atoms. In this case the two atom (carbon) bridge is additionally annellated with a carbocycle and/or heterocycle. The three atom bridge contains three C atoms or two C atoms and one O atom without additional annellation. Both rings may carry a plurality of substituents.
However, the wide variety of photochromic dyes that are available in the state of the art have drawbacks that have a significant negative effect on the wearing comfort of the spectacle wearer when these photochromic dyes are used in ophthalmic sunglass lenses. First of all, the dyes have an inadequate long-wave absorption in the excited as well as in the unexcited state. Secondly the temperature sensitivity with respect to the darkening is too high. At the same time, the brightening is frequently too slow. In addition, the dyes that are available in the state of the art have an inadequate service life and, hence, permit only negligible durability in ophthalmic sunglass lenses. The latter becomes noticeable in the rapid decrease in performance and/or in severe yellowing.